Introduce SSLEngine configuration hook for NIO

src/main/java/com/rabbitmq/client/SslEngineConfigurator.java

@@ -0,0 +1,30 @@
+// Copyright (c) 2017-Present Pivotal Software, Inc.  All rights reserved.
+//
+// This software, the RabbitMQ Java client library, is triple-licensed under the
+// Mozilla Public License 1.1 ("MPL"), the GNU General Public License version 2
+// ("GPL") and the Apache License version 2 ("ASL"). For the MPL, please see
+// LICENSE-MPL-RabbitMQ. For the GPL, please see LICENSE-GPL2.  For the ASL,
+// please see LICENSE-APACHE2.
+//
+// This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND,
+// either express or implied. See the LICENSE file for specific language governing
+// rights and limitations of this software.
+//
+// If you have any questions regarding licensing, please contact us at
+// info@rabbitmq.com.
+
+package com.rabbitmq.client;
+
+import javax.net.ssl.SSLEngine;
+import java.io.IOException;
+
+public interface SslEngineConfigurator {
+
+    /**
+     * Provides a hook to insert custom configuration of the {@link SSLEngine}s
+     * used to connect to an AMQP server before they connect.
+     * Note this is used only when NIO are in use.
+     */
+    void configure(SSLEngine sslEngine) throws IOException;
+
+}

src/main/java/com/rabbitmq/client/impl/nio/NioParams.java

@@ -17,7 +17,10 @@
 
 import com.rabbitmq.client.DefaultSocketChannelConfigurator;
 import com.rabbitmq.client.SocketChannelConfigurator;
+import com.rabbitmq.client.SslEngineConfigurator;
 
+import javax.net.ssl.SSLEngine;
+import java.io.IOException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ThreadFactory;
 
@@ -51,6 +54,12 @@ public class NioParams {
     /** the hook to configure the socket channel before it's open */
     private SocketChannelConfigurator socketChannelConfigurator = new DefaultSocketChannelConfigurator();
 
+    /** the hook to configure the SSL engine before the connection is open */
+    private SslEngineConfigurator sslEngineConfigurator = new SslEngineConfigurator() {
+        @Override
+        public void configure(SSLEngine sslEngine) throws IOException { }
+    };
+
     public NioParams() {
     }
 
@@ -62,6 +71,7 @@ public NioParams(NioParams nioParams) {
         setWriteQueueCapacity(nioParams.getWriteQueueCapacity());
         setNioExecutor(nioParams.getNioExecutor());
         setThreadFactory(nioParams.getThreadFactory());
+        setSslEngineConfigurator(nioParams.getSslEngineConfigurator());
     }
 
     public int getReadByteBufferSize() {
@@ -248,4 +258,21 @@ public void setSocketChannelConfigurator(SocketChannelConfigurator configurator)
     public SocketChannelConfigurator getSocketChannelConfigurator() {
         return socketChannelConfigurator;
     }
+
+    /**
+     * Set the {@link SSLEngine} configurator.
+     * This gets a change to "configure" the SSL engine
+     * before the connection has been opened. This can be
+     * used e.g. to set {@link javax.net.ssl.SSLParameters}.
+     * The default implementation doesn't do anything.
+     *
+     * @param configurator the configurator to use
+     */
+    public void setSslEngineConfigurator(SslEngineConfigurator configurator) {
+        this.sslEngineConfigurator = configurator;
+    }
+
+    public SslEngineConfigurator getSslEngineConfigurator() {
+        return sslEngineConfigurator;
+    }
 }

src/main/java/com/rabbitmq/client/impl/nio/SocketChannelFrameHandlerFactory.java

@@ -70,6 +70,9 @@ public FrameHandler create(Address addr) throws IOException {
             if (ssl) {
                 sslEngine = sslContext.createSSLEngine(addr.getHost(), portNumber);
                 sslEngine.setUseClientMode(true);
+                if (nioParams.getSslEngineConfigurator() != null) {
+                    nioParams.getSslEngineConfigurator().configure(sslEngine);
+                }
             }
 
             SocketAddress address = new InetSocketAddress(addr.getHost(), portNumber);

src/test/java/com/rabbitmq/client/test/ssl/NioTlsUnverifiedConnection.java

@@ -16,15 +16,17 @@
 package com.rabbitmq.client.test.ssl;
 
 import com.rabbitmq.client.*;
+import com.rabbitmq.client.impl.nio.NioParams;
 import com.rabbitmq.client.test.BrokerTestCase;
-import org.junit.Assert;
 import org.junit.Test;
 import org.slf4j.LoggerFactory;
 
+import javax.net.ssl.SSLEngine;
 import java.io.IOException;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -66,6 +68,32 @@ public void connectionGetConsume() throws Exception {
         assertTrue("Message has not been received", messagesReceived);
     }
 
+    @Test public void socketChannelConfigurator() throws Exception {
+        ConnectionFactory connectionFactory = new ConnectionFactory();
+        connectionFactory.useNio();
+        connectionFactory.useSslProtocol();
+        NioParams nioParams = new NioParams();
+        final AtomicBoolean sslEngineHasBeenCalled = new AtomicBoolean(false);
+        nioParams.setSslEngineConfigurator(new SslEngineConfigurator() {
+            @Override
+            public void configure(SSLEngine sslEngine) throws IOException {
+                sslEngineHasBeenCalled.set(true);
+            }
+        });
+
+        connectionFactory.setNioParams(nioParams);
+
+        Connection connection = null;
+        try {
+            connection = connectionFactory.newConnection();
+            assertTrue("The SSL engine configurator should have called", sslEngineHasBeenCalled.get());
+        } finally {
+            if (connection != null) {
+                connection.close();
+            }
+        }
+    }
+
     private Connection basicGetBasicConsume(Connection connection, String queue, final CountDownLatch latch)
         throws IOException, TimeoutException {
         Channel channel = connection.createChannel();